1. Field of the Invention
This invention relates to a corrosion-resistant member used in a region in which a gas or a plasma of a halogen-containing compound is used in a process for producing semiconductors, especially a member used as jigs such as a supporter for supporting a material to be treated, or as an inner wall member in an apparatus for producing semiconductors, which has a high corrosion resistance to a fluorine type or a chlorine type corrosive gas, or a fluorine type or a chlorine type plasma.
2. Prior Art
A process used in the production of highly integrated circuit elements such as semiconductor elements, including a dry process and a plasma process utilizing a plasma such as plasma coating, has been rapidly advanced in recent years. As the plasma process in the production of semiconductors, a halogen-type corrosive gas such as the fluorine type has been utilized in vapor deposition, etching or cleaning because of its high reactivity.
Members to be contacted with corrosive gases are required to have high corrosion resistance. As members to be contacted with the plasma in addition to the material to be treated generally include materials containing SiO.sub.2 as a main component such as glass or quartz, or metals such as stainless steel or Monel.
In the production of semiconductors, as susceptor for holding and fixing a wafer, an alumina fired product, sapphire, a sintered product of AlN, and surface coated products of the above products by the CVD method are used because they have an excellent corrosion resistance. Furthermore, heaters obtained by coating graphite and boron nitride are used.
However, glass and quartz used heretofore have insufficient corrosion resistance and are consumed violently, and when they contact a gas or a plasma of a halogen compound, especially a fluorine or chlorine plasma, the contacting surface is etched, and the surface properties will change. Therefore, production conditions for the semiconductor, and especially etching conditions will be affected. Since a member using a metal such as stainless steel has insufficient corrosion resistance, corrosion causes the occurrence of poor products especially in the production of semiconductors.
Although sintered products of alumina and AlN have excellent corrosion resistance to fluorine-type gases as compared with the above materials, when they contact the plasma at high temperatures, their corrosion gradually proceeds and the removal of crystal particles occurs from the surface of the sintered products, and this becomes a cause of the occurrence of particles.
The occurrence of particles, even very fine particles formed by ion bombardment or reaction in a gaseous phase, becomes a cause of inconveniences such as the deterioration of properties of an element such as disconnected metal wirings or defects of pattern, or the reduction of the yield which occur by the high integration of a semiconductor and a further cleaning of the process.
To solve this problem, the present inventors proposed to form a corrosion resistant member from a material composed of 2A and 3A elements of the periodic table as a main component which forms a halogen compound stable to the surface of the material against a fluorine or chlorine-type plasma. However, the material composed of elements of Group 2A and 3A of the periodic table as main component is stable to a fluorine or chlorine-type plasma, but has a defect that the removal of a halogen compound formed on the surface of the material or a reaction in a vapor phase causes the occurrence of particles.